问题 选择题

燃料电池是一种高效、环境友好的发电装置,它的原理是原电池原理,可进行能量的转换.以CH4为燃料时,另一极通入氧气,以KOH为电解质溶液,产物为碳酸钾和水,二氧化碳的排放量比常规发电减少40%以上.下列有关燃料电池的说法正确的是(  )

A.通入甲烷的一极是燃料电池的负极

B.燃料电池是将热能转换为电能的装置

C.通入氧气的一极是燃料电池的负极

D.该燃料电池使用一段时间后,溶液的pH值增大

答案

反应的总方程式为CH4+2O2+2OH-=CO32-+3H2O,则

A.根据化合价的变化可知,原电池工作时,通入甲烷的一极为原电池的负极,发生氧化反应,故A正确;

B.甲烷燃料电池是将化学能转化为电能的装置,故B错误;

C.根据化合价的变化可知,原电池工作时,通入氧气的一极为原电池的正极,发生还原反应,故C错误;

D.根据总反应式可知,反应消耗KOH,溶液pH值减小,故D错误.

故选A.

单项选择题

"The imperative to self-knowledge has always been at the heart of philosophical inquiry," wrote MIT professor Sherry Turkle in the insightful book about the web and the self, Life on the Screen: Identity in the Age of the Internet. Published in 1995 as the second part of a trilogy that examined our relationships with technology, it looked at how we are who we are in online spaces. And what that means for us offline.

The good news is that the results are positive: "Play has always been an important aspect of our individual efforts to build identity," she said, referencing developmental psychologist Erik Erikson, and nodding to the theories of psychoanalysts Freud, Lacan and Jung. "In terms of our views of the self," she wrote, "new images of multiplicity, heterogeneity, flexibility, and fragmentation dominate current thinking about human identity. "

At the time Life on the Screen was released, most of the visitors were college students and their professors from a remarkably small talent pool, and a surprisingly small geography. They were tech-savvy, and generically open-minded about the new fields of virtual exploration that lay within the networks of this new communication platform. They were, in other words, liberal, enlightened types who were more willing to embrace the unprecedented fluidity of self-expression that this new technology uniquely afforded.

As a psychoanalyst and a web user herself, Turkle spent much of the book explaining why the articulation of multiple personalities wasn’t pathological. Contrary to its Latin root, identity need not mean "the same", she argued. "No one aspect can be claimed as the absolute, true self", she wrote, maintaining that the web allowed us the opportunity to get to know our "inner diversity". In the great psychoanalytic tradition, she said that self-actualisation meant coming to terms with who we are, and integrating each aspect of it into a coherent and well-integrated us.

Almost everyone has experienced this kind of identity play. Even if you’ve never ventured into an online game or been a signed-up member of a web community, you’ve probably developed a profile for a social network, written a blog, styled a website, commented on an article. But things are different from the time when Turkle was writing Life on the Screen. Nowadays, our virtual social lives are increasingly integrated. with our offline social lives. The freedom of expression is curtailed by the threat of offline consequences from online actions. Today, your reputation offline is far more closely tied to your reputation online than before. In fact, our experience of contemporary identity online is disarmingly similar to offline.

However, I still subscribe to the old Turkle. Consequence-free online environments allow us to practise and play without fear of offline effect, and offer an extraordinary place to experience the fluidity of our selves: I can be anyone, even a dog. As Tom MacMaster found, there still are places online where this is possible.

The text is most likely to be()

A. a scientific report

B. a review of a book

C. a description of a new phenomenon

D. an account of a personal experience

判断题